Despite attempts to disguise his voice, experts said it was clear he was the same man who murdered Foley.

Sotloff was forced to speak to the camera before he died.

Speaking directly to Obama in a calm voice, he said: “I am paying the price of your interference with my life. You’ve spent billions of US taxpayers’ dollars and we have lost thousands of our troops in our previous fighting against the Islamic State, so where is the people’s interest in reigniting this war?”

Sotloff, a 31-year-old freelance writer from Miami who worked for magazines including Time, was kidnapped near Aleppo in northern Syria in August last year.